Is colorectal cancer increasing in young adults in the US?

The rise in younger adults stands out because, for decades, colorectal cancer was mostly seen in people over 50. Now, it’s becoming more common in people in their 20s, 30s, and 40s. We don’t know why this shift is happening — the evidence we’ve reviewed doesn’t explain causes like diet, lifestyle, or genetics. We also don’t know if this trend will continue or if it’s due to better detection, changes in risk factors, or something else.

What we’ve found so far leans toward a real and growing concern in this younger group. But we can’t say what’s driving it, or whether it’s happening in other countries or just the U.S. The data we have is limited to U.S. trends and doesn’t include global comparisons or long-term projections.

For now, the clearest takeaway is this: if you’re under 50 and notice changes in bowel habits, unexplained weight loss, or persistent fatigue, it’s worth talking to a doctor — not because you’re likely to have cancer, but because early signs are easier to treat when caught early.